British Transport Police is appealing for information after a member of station staff was assaulted on board a train at Southend Victoria station.
Investigators have released CCTV of a man they would like to speak to in connection with the incident, which took place on Monday, 25 March.
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Tuesday lunchtime's weather for the west for the region
Tuesday lunchtime's weather for the east for the region
Work officially begins to decontaminate nine areas of the city which experts believe traces of the agent still remain.